From Tropical Topics newsletter, No. 80,
January 2004, produced by Stella Martin at the Queensland
Environmental Protection Agency. Download the PDF to read the whole
issue.
There are at least 65 species of elapid snakes in Australia,
though further study is likely to increase this number
considerably; some scientists currently recognise 90. They are all
characterised by fixed front fangs and are all venomous, though
only about 20 are considered potentially fatal to humans. Many are
small. Most elapids are ground dwellers — only three
species are regularly found in trees, although some others will
climb up, especially when threatened by flooding.
Brown snakes
Not all brown snakes are brown. Indeed, they are very variable
in appearance. Members of the same species can be orange or almost
black, striped or plain and even hatchlings from the same clutch of
eggs can look different. Their most distinctive feature is their
pronounced brow ridge. Brown snakes are the cause of most snake
bite fatalities in Australia.
The eastern brown snake (Pseudonaja textilis) which
inhabits most of the eastern half of the continent, is one of
Australia’s most dangerous snakes. It is common in farming
areas, towns and suburbs — it is fond of house mice —
and becomes very aggressive when threatened. However, its offensive
temperament has probably been overstated.
Like all snakes, it prefers to quietly disappear. A study in New
South Wales found that half of all eastern brown snakes retreated
when people came near, many others remained stationary and only
three percent moved towards the intruder. Less than one per cent
behaved aggressively, usually after being touched or trodden upon.
Nonetheless, when cornered this snake is impressively assertive,
hissing, rising up and striking rapidly.
Western brown
The western brown snake (Pseudonaja nuchalis) is found
widely throughout Australia in arid, semi-arid and even wet
sclerophyll areas, but is absent from much of the east coast.
However, there are thought to be at least seven distinct groups and
because at least three cannot interbreed, they are almost certainly
different species. Colours are variable and these snakes tend to be
darker in winter and paler in summer. The western brown is active
by day, but nocturnal in hot weather, and eats lizards and small
mammals, such as house mice, birds and small snakes. It is shy and
reluctant to bite humans unless cornered. Although it has long
fangs and delivers a large amount of venom, it is less toxic than
that of the eastern brown.
Mulga snake
The mulga snake (Pseudechisaustralis) is also commonly known as
the king brown. It is not one of the brown snake group but instead
belongs to the ‘black snake’ genus (not all of which
are black!). It is Australia’s most widespread snake and can
be found throughout much of the continent. It is a large snake;
individuals in the Northern Territory and Cape York Peninsula grow
to almost three metres. The mulga snake feeds on other snakes,
quickly killing them with its venom although it is apparently not
vulnerable to their toxins. It also eats lizards, small mammals,
birds and frogs. Numbers appear to be dropping in areas colonised
by the poisonous cane toad.
Death adders
Death adders (Acanthophis spp) are the closest thing we
have to vipers in Australia. In addition to their teeth they also
resemble these dangerous snakes in shape, behaviour and ecology
— but they are not related.
Death adders are ambush predators which hide curled, in leaf
litter. The end of a death adder’s tail abruptly narrows to a
worm-like lure and when potential prey such as lizards, birds,
mammals or frogs come near the snake flicks this lure. Mistaking it
for a tasty morsel, for example an insect larva, the duped animal
often pounces, only to find itself swiftly pounced upon.
This ambush habit of the death adder means that it does not,
like other snakes, retreat when people come near. However, it seems
reluctant to bite people, even when gently trodden upon.
Nevertheless, a bite from a death adder is a very dangerous one and
should be avoided.
There are three species of death adders in Australia. They vary
in colour with grey ones more abundant in cooler areas where their
colour may help them to warm up quickly. Reddish coloured ones are
more common in hotter areas.
